1. Field of the Invention
The present invention relates to a sewing machine needle, especially for industrial sewing machines, comprising a piston for clamping the needle into the respective sewing machine and a conical portion connected to the piston and forming a transition into the needle shaft. The needle shaft comprises a shaft portion and an end piece, with a needle eye for receiving a sewing thread being disposed between the shaft portion and the end piece.
2. Description of the Related Art
In the industrial finishing section of the sewing industry a high sewing speed is desired for economical reasons which leads to a heating of the sewing machine needle. This heating of the sewing machine needle results from the friction between the needle and the textile material being sewn and poses a plurality of problems for the sewing industry. A high needle temperature not only results in heat damage to natural fibers, but also causes softening and melting of synthetic fibers. Further disadvantages of high needle temperatures are not only the rupture of the threads during sewing of synthetic fibers, but also the deposition of melted particles of the synthetic fiber material at the needle, especially within the needle eye or within the thread guiding groove which ultimately leads to the needle being unsuitable for further use. Furthermore, the needle itself is effected by the high needle temperature because its hardness is reduced so that a deformation or bending of the needle or even breakage can occur.
The magnitude of the needle heating generated at the contact area between the needle and the textile material depends mainly on the following factors: Textile sizing, textile density, number of textile layers to be sewn, thread sizing, and primarily the sewing speed. These factors cannot be influenced by the sewing needle.
It is therefore an object of the present invention to prevent the heating of the sewing machine needle caused by the aforementioned factors by a special needle design and to provide thereby a reduced thermal load at the sewing thread and the textile material as well as at the needle even under the high loads experienced by the sewing machine needles.